Switching to rVIII-SingleChain Ensures Bleeding Protection and may Reduce Injection Frequency or Consumption in Hemophilia A Patients: Real-world Clinical Experience in Adults/Adolescents and Pediatric Patients

Scientific Research Question: rVIII-SingleChain is a novel B-domain truncated recombinant factor VIII in which heavy and light chains are covalently linked, resulting in an increased stability and a high binding affinity for von Willebrand factor. In clinical trials, rVIII-SingleChain has been shown to be efficacious for the treatment and prevention of bleeds in patients with hemophilia A, and to have a favorable safety profile. Data on the use of rVIII-SingleChain for the treatment of hemophilia A patients in a real-world clinical setting is missing thus far. Here we summarize our experience when switching adults/adolescents (Bonn Center) and children (Munich Center) to rVIII-SingleChain.

Methodology: Adults/adolescents from the Bonn Center (n = 11) and children from the Munich Center (n = 12) with severe hemophilia A were switched to rVIII-SingleChain and their clinical response and tolerability to rVIII-SingleChain treatment was reported.

Findings: Switching to rVIII-SingleChain proceeded without any problems in both adults/adolescents and children. rVIII-SingleChain was shown to be effective for prophylaxis and in the treatment of bleeding episodes. In 91% (10/11) of adult/adolescent patients a reduction in injection frequency was possible and most patients (73%) were able to reduce or maintain their weekly factor consumption of rVIII-SingleChain. In children, injection frequency was maintained in 83% (10/12) of patients and dose reduction has thus far been initiated in some children (4/12). rVIII-SingleChain was well tolerated; there were no safety events and no patients developed inhibitors.

Conclusions: Within our two centers, the transition to rVIII-SingleChain was straightforward; effective bleed control was achieved across all age groups. In adults/adolescents, rVIII-SingleChain provided the opportunity for reductions in both injection frequency and dose, thereby reducing treatment burden of patients; whereas in children it offered the possibility for dose reduction in some patients.